The present invention concerns an improved metal complexes of the fungicide 1-[N-propyl-N-2-(2,4,6-trichlorophenoxy)-ethyl-carbamoyl]-imidazole, known by the common name prochloraz, its improved formulations and their use in combating fungi, especially powdery mildew (Sphaerotheca fuliginia) and coffee berry disease (Colletotrichum coffeanum).
Prochloraz is a protectant and eradicant fungicide, effective against a wide range of diseases affecting field crops, fruit, turf and vegetables. Its use was first reported in United Kingdom patent numbers 1,469,772 and 1,576,277, whose contents are incorporated by their mention. Prochloraz is sold under two different types of formulation. One form is an emulsifiable concentrate, which contains the free compound as active ingredient. The second formulation is a wettable powder where the active ingredient is in the form of a metal complex. The metal complexes of prochloraz were first reported in United Kingdom patent number 1,567,521 (Israel patent no. 54,304), whose contents are incorporated by its reference.
The metal complexes of prochloraz were intended to solve two problems found in using the free, non-complexed prochloraz. The first was, that non-complexed prochloraz was found difficult to handle and formulate on a solid powder carrier. It was found necessary to first absorb it on a carrier prior to preparing a powder, causing loss of material, lowering the fungicidal activity and preventing the preparation in a highly concentrated form. The second problem was that free, non-complexed prochloraz was found to be phytotoxic to some crops. However, the metal complexes of prochloraz were found to avoid these problems. Thus the metal complexes of prochloraz, generally were found to be solid, distinctly melting compounds, readily formulated with a solid carrier or concentrate, without the phytotoxic problems found on susceptible crops.
Patent coverage on the metal complexes of prochloraz was obtained in many countries (i.e. GB 1,567,521 and U.S. Pat. No. 4,250,179). The metals exemplified or disclosed were divalent metals such as copper, manganese, iron, nickel and cobalt. Nowhere were metal salts of SnCl.sub.2 or ZnCl.sub.2 with prochloraz disclosed or claimed. Indeed, there are indications from the prior art that these specific salts cannot be prepared. With regard to the cobalt complex, while it was disclosed, it was not claimed, nor was this complex exemplified. Thus, the present invention is a selection patent of those patents covering metal complexes of prochloraz.